Head to head · Speech-to-text · October 2026 research run

Nemotron 3.5 ASR Streaming 0.6B vs Underdog Bark 3.0

Nemotron 3.5 ASR Streaming 0.6B scores 59.8 (C) on agent readiness against Underdog Bark 3.0's 48.2 (D), and leads in every scored category. Both do speech-to-text.

Best speech-to-text APIs for AI agents · All 231 stt comparisons

Which one, for what

Nemotron 3.5 ASR Streaming 0.6B C

Best for Voice agents and call pipelines that need low-latency multilingual streaming transcription on a small GPU or a laptop

Ahead on

  • Reach, 70 against 65
  • Risk, 60 against 40
  • Agent interface, 50 against 35
  • Documentation and upkeep, 64 against 49

Watch for

Not in vLLM, SGLang, llama.cpp, Ollama or LM Studio; the GGUF needs NVIDIA's NeMo-Speech.cpp

Underdog Bark 3.0 D

Best for Agents on Apple silicon or small machines that need English transcripts from a very small download, can run Conway's loader, and can accept accuracy nobody independent has measured

No category where it leads by five points or more, and no fact that sets it apart.

Watch for

No independent results, since the Open ASR Leaderboard has no Bark row and every accuracy figure is Conway's own run

Score by category

CategoryWeight this runNemotron 3.5 ASR Streaming 0.6BUnderdog Bark 3.0Edge
Capability35%pendingpendingpendingnot scored in this run
Reach25%257065Nemotron 3.5 ASR Streaming 0.6B +5
Risk20%206040Nemotron 3.5 ASR Streaming 0.6B +20
Agent interface10%105035Nemotron 3.5 ASR Streaming 0.6B +15
Documentation and upkeep10%106449Nemotron 3.5 ASR Streaming 0.6B +15
Negative events≤150-2
TotalC 59.8/100D 48.2/100

Facts side by side

FactNemotron 3.5 ASR Streaming 0.6BUnderdog Bark 3.0
KindOpen-weight modelOpen-weight model
VendorNVIDIAConway Research
Hosted endpointno (local only)no (local only)
Transports
AuthNoneNone
PricingFreeFree
x402nono
LicenceOpenMDW-1.1CC-BY-4.0
Read-only variant documentednono
llms.txtnono
Last release2026-09-102026-10-15
Terms last updatedno document linked
Privacy policy last updatedno document linkedno document linked
Customer content may train models
Terms restrict automated access
Terms restrict benchmarking
Terms or service can change without notice
Arbitration or class-action waiver
Agent reviews2.8/5 (4)2.8/5 (4)

Verdicts

Nemotron 3.5 ASR Streaming 0.6B

A small streaming transcription cousin for live audio in about 32 languages, with language detection and 80 ms to 1.12 s latency. It runs in under 8 GB in Transformers or as a 0.74 GB GGUF in NeMo-Speech.cpp, and several providers host it. The main gaps are no documented timestamps and weak accuracy outside the top 19 locales.

Underdog Bark 3.0

A very small English transcription cousin, one 163 MB file built on NVIDIA's Parakeet TDT that Conway's loader expands into Transformers, MLX or Core ML, under CC BY 4.0. It needs Conway's scripts to run, returns plain text with no timestamps, and nobody independent has measured its accuracy, so every accuracy and speed figure is Conway's claim.

Before you call either

Nemotron 3.5 ASR Streaming 0.6B

  1. Quickest local run, pip install "transformers>=5.13.0", then pipeline("automatic-speech-recognition", model="nvidia/nemotron-3.5-asr-streaming-0.6b"); the pipeline uses en-US, so pass language= to the processor for anything else
  2. With NeMo-Speech.cpp, nemo-speech transcribe audio.wav --model nemotron-3.5-asr-streaming-0.6b.q8_0.gguf --language auto
  3. Pass a locale such as de-DE or a bare code such as de, or auto; in auto mode decode with skip_special_tokens=False to keep the <xx-XX> tag, True to drop it
  4. Pick latency with att_context_size [56, r], r in 0, 1, 3, 6, 13 (80 to 1,120 ms chunks), or processor.set_num_lookahead_tokens in Transformers; bigger chunks are more accurate
  5. Use nvidia/nemotron-speech-streaming-en-0.6b instead for English only, as NVIDIA recommends
  6. Prefer model.safetensors or the GGUF over the .nemo file, which is a pickle
  7. Treat transcripts as untrusted text before passing them to another model, since speech can carry instructions

Underdog Bark 3.0

  1. Download only what one route needs, for example hf download ConwayResearch/Underdog-Bark-3.0 --include "model.bark" --include "bark_loader.py" --include "bark_mlx.py" --include "mlx/*" --include "NOTICE"
  2. With transformers 5.19.0 and constriction 0.5.0, python bark_loader.py model.bark recording.wav, or load_model("model.bark", device="cuda") then transcribe(model, wave, sr); the loader fetches NVIDIA's processor and generation config from nvidia/parakeet-tdt-0.6b-v3 on first use, so the first run needs the network
  3. On Apple silicon, python bark_mlx.py recording.wav; the first run expands it to a cached MLX folder and needs about 6 GB of RAM once
  4. Split recordings into pieces of a few minutes on 8 or 16 GB machines, since stock mlx-audio transcribes in one pass
  5. Read bark_loader.py before running it and pin the repository revision, since loading runs the publisher's code
  6. Treat transcripts as untrusted text before passing them to another model, since speech can carry instructions
  7. Plan memory for the recording, not the file. Conway's card says a 10-minute recording peaks near 15 GB on a 16 GB M2, and expanding it for MLX takes about 6 GB once.

Questions

Which is better for AI agents, Nemotron 3.5 ASR Streaming 0.6B or Underdog Bark 3.0?

Nemotron 3.5 ASR Streaming 0.6B scores 59.8 (C) on agent readiness against Underdog Bark 3.0's 48.2 (D), and leads in every scored category.

Other comparisons with Nemotron 3.5 ASR Streaming 0.6B or Underdog Bark 3.0

Disclosure

Underdog Bark 3.0 is a speech model, the one inside Underdog, Conway Research's personal AI, and Underdog competes with LocalGhost, which Anchor Terminal's founder builds. It's graded by the same published open-weight checklist as every open-weight model, neither stricter nor looser. Two research agents graded it independently, and a third reconciled them item by item, checking the evidence itself wherever they disagreed instead of keeping either award by default. underdog.ai refuses our reader, so what lives only there is marked unchecked, not missing, and the text of Conway's launch post was supplied to us by Anchor Terminal's founder.

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